The Scientific Core (Core 2) is the scientific research-support core and will be utilized by all of the Projects (1 of through the emphasis 5) to various on yeast extents and (see bacteria Table l-SC). l model systems for defining the DNA damage-resistance circuitry responding to genotoxic stress, there will be a major requirement for a microbiological core facility for the production of a large number of yeast and bacteriological plates of various standard and specialized media. Almost all of the Projects (1, 2, 4, and 5) will require the use of a dedicated cell disruption system for the preparation of yeast and bacterial cell extracts for biochemical and molecular biological analyses. In addition, the investigators located in the Rollins Research Center (Projects 1 and 2) and the adjacent Whitehead Research Building (Project 4) will require frequent use and the other investigators will require occasional use (Projects 3 and 5) of a quantitative imaging system for various purposes including the analysis of Western blots, silver-and Coomassie-stained SDS-PAGE gels, DNA agarose gels, and cellular micro-well plate assays using fluorescence, chemiluminescence, densitometric and colorimeteric methodologies. The investigators believe that meeting these requirements, which is key to the success of this Program Project, can be accomplished best by a dedicated Scientific Core of several instruments, staffed by a full time research specialist devoting 50% of their effort towards the Program Project. Since it is also envisioned that this individual will also be used by the five project groups to prepare plates and media for studies outside of the Program Project area, the balance of the Research Specialist 's salary as well as supplies for materials will be covered by other funds from these investigator's programs to cover non-Program Project-related usage (see Table 2-SC). In addition, access to this facility will be available to local research groups outside of the program project on a fee-for-service basis. The physical location of the Scientific Core will be RRC 4075 (location of the sterilizer/plate pourer unit and the Multi-Imager system) and a portion of the adjoining cold room RRC 4073 (location of the French Press cell disruptor) located on the 4th Floor of the Rollins Research Center in close proximity to the Doetsch, Jinks-Robertson, and Shadel laboratories. Ample bench space is available to accommodate this equipment as well as desk space for the Research Specialist. These facilities were shown to the site-visit team in February 2001.